Some people pay absurdly high prices for items primarily to show they can. But most of us use other criteria to weigh up the benefits relative to the cost in deciding what to buy. Eduardo Porter shows how price lies behind all the choices we make. 'The price we put on things,' he writes, 'says a lot about who we are', and the poor choose among their options the same way the rich do. If all that seems obvious, Porter, who is on the editorial board of The New York Times, also offers much that might surprise readers. For instance, you might know that life has a price tag, but possibly not that the next of kin of 2,800 victims of the 9/11 terrorist attacks in the US were paid US$2 million on average, while the families of victims who earned more than US$4 million a year received US$6.4 million, and that of the 'cheapest' victim were awarded only US$250,000. From the price of life (and death), Porter moves into that for happiness, work, culture, faith, the future and women (who are more valuable than ever). He also analyses 'the price of free', in which he shows how, counterintuitively, things that are offered gratis can bump up profits.